Generally, in the iontophoresis treatment, a liquid or a gel containing the medication is made contact with a human skin (skin and mucosa), and an electric current is applied there, such that the medication ionically migrate into the skin, or into the body through the skin. An electrode device used in this treatment comprises an electrode layer and a medication reservoir layer, wherein the electrode layer is electrically charged from an external electric supply. The medication reservoir layer retains the ionized medication, thus having electric conductivity, and functions as an electrode device together with the electrode layer.
The medication reservoir layer can be in the form of a liquid or a gel. The medication reservoir layer is made contact with the electrode layer to function as a part of the electrode device, while introducing the medication retained therein into the skin. Therefore, the medication reservoir layer is needed to be firmly secured to the electrode device. Thus, there hitherto have been made various attempts to prevent the medication reservoir layer from leaking, peeling or dropping from the electrode device.
Patent Publication 1 discloses the use of a sheet substrate having a recess filled with a liquid or a gel (a medication reservoir layer). However, since the substrate having the recess is often turned upside down in practical use, the gel filling the recess is likely to flow down or drop off the recess.
Patent Publication 2 proposes an idea, wherein a non-woven fabric of a porous material is laminated on an electrode layer, and this non-woven fabric is impregnated with gel to thereby prevent the gel from dropping off. This publication also proposes an idea to mount a guide after the non-woven fabric is impregnated with the gel, the guide is for preventing the gel from dropping off.
Patent Publication 3 proposes a method, wherein a circular cup-shaped chamber is filled with a medication reservoir layer, and the chamber is closed with an ion permeable film. In Patent Publication 4, viscous gel is used to enhance the adhesive strength between an electrode layer and a medication reservoir layer.